BIOS enabling SATA2 Drive causes boot error if no actual drive in SATA2 socket - Optiplex 780 Win 7

[glnz]

Today, in my Optiplex 780 Desktop with Win 7 Pro 64-bit and 8GB RAM, I cloned my hard drive from old drive to new drive.  To do that, I went into BIOS (which is the A14 version), went to Drives, enabled SATA2, and plugged the new empty hard drive into the SATA2 socket on the motherboard.  The original drive has always been in the SATA0 socket, and the CD-DVD has always been in the SATA1 socket.

The clone went well (using Macrium Reflect Free in a USB stick).  When I took out the old drive and connected the new cloned drive to the original SATA0 socket, the Optiplex gave me errors on the reboot.  It said it was missing a drive in SATA2 and did i want to Continue, go into System or run Diagnostics.  After a few reboots with that error, I went back into BIOS - Drives and disabled SATA2.  Then reboot went very well without errors, a few times.  All good.

However, those errors aren't right.  I should be able to enable SATA2 in BIOS and not get errors just because no actual drive is plugged into the SATA2 socket on the motherboard.  (That's how it works in a different Dell Optiplex 3010 I have).

So what's going on?  Why am I getting this error?

(By the way, the old drive was a 10-year old Maxtor 500GB, and the new drive is a Seagate Firecuda ST1000DX002.  Do you think the SATA2 socket fell so in love with the Firecuda that it just can't let go?)

Thanks.

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Edited November 14, 2016 by glnz

[jaclaz]

Is that BIOS or UEFI?

IF UEFI, check NVRAM, maybe that disk boot manager was added to it, and now it looks for it and throws a fit

http://superuser.com/questions/930725/how-to-delete-os-from-boot-menu
 

jaclaz